In leave setting, you can create various custom leave.

To create custom leave,
( 1 ) Go to Settings.

( 2 )Select Leave , and click Create custom leave.

( 3 )Fill the leave type name and description.(example., Education leave, medical leave,.....)

( 4 )When you are done above steps, go to Policies under setting.

( 5 )When you are in policy, select the leave type that you have created .

( 6 )when you are in that leave setting,you can set day available and maximum days, and customize the policy as you want( like you will allow half-Day leave for that leave type,and leave generate method ,etc..)
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But there is a condition in here, after you've already finished these step, and just click the confirm ,this policy won't be published.
If you want to publish, you have to click Save and Regenerate.

( 7 )After Save and Regenerate, you will see this page and ,in here, you can update days allowed for each employees.

( 8 )And just click Confirm.

If your company have different leave policy for probation and permanent employees, you can do as this article.